Maintaining arm control during self-triggered and unpredictable unloading perturbations.

We often perform actions where we must break through some resistive force, but want to remain in control during this unpredictable transition; for example, when an object we are pushing on transitions from static to dynamic friction and begins to move. We designed a laboratory task to replicate this situation in which participants actively pushed against a robotic manipulandum until they exceeded an unpredictable threshold, at which point the manipulandum moved freely. Human participants were instructed to either stop the movement of the handle following this unloading perturbation, or to continue pushing.

Clinical outcome and factors determining new bone formation in lateral sinus membrane elevation with simultaneous implant placement without grafting material: A cross-sectional, 3-17 year follow-up study.

Background: Lateral sinus membrane elevation with simultaneous implant placement without grafting material (graft-less LSFE) is a widely investigated method for bone augmentation of the maxillary sinus floor. Long-term follow-up studies are rare.

Purpose: This study aimed to investigate the long-term effects of implants placed with graft-less LSFE.

Biting intentions modulate digastric reflex responses to sudden unloading of the jaw.

Reflex responses in jaw-opening muscles can be evoked when a brittle object cracks between the teeth and suddenly unloads the jaw. We hypothesized that this reflex response is flexible and, as such, is modulated according to the instructed goal of biting through an object. Study participants performed two different biting tasks when holding a peanut half stacked on a chocolate piece between their incisors.

Task-dependent control of the jaw during food splitting in humans.

Although splitting of food items between the incisors often requires high bite forces, rarely do the teeth harmfully collide when the jaw quickly closes after split. Previous studies indicate that the force-velocity relationship of the jaw closing muscles principally explains the prompt dissipation of jaw closing force. Here, we asked whether people could regulate the dissipation of jaw closing force during food splitting.

Impaired masticatory behavior in subjects with reduced periodontal tissue support.

Background: Mechanoreceptors situated in the periodontal ligament provide detailed information about intensive and spatial aspects of tooth loads, which support the neural control of masticatory forces. We asked whether a reduced periodontal ligament due to periodontitis, and, thus, an altered mechanoreceptive innervation of the teeth, would affect masticatory behavior when subjects used incisors to hold and split food.

Methods: We tested 11 subjects with reduced periodontal tissue support that rendered 30% to 70% alveolar bone loss for at least one pair of opposing anterior incisors.

Predicting aflatoxin and fumonisin in shelled corn lots using poor-quality grade components.

A study was conducted to determine if aflatoxin and fumonisin are concentrated in the poor-quality grade components of shelled corn. Four 1.0 kg test samples were each taken from 23 lots of shelled corn marketed in North Carolina.

Sampling uncertainties for the detection of chemical agents in complex food matrices.

Using uncertainty associated with detection of aflatoxin in shelled corn as a model, the uncertainty associated with detecting chemical agents intentionally added to food products was evaluated. Accuracy and precision are two types of uncertainties generally associated with sampling plans. Sources of variability that affect precision were the primary focus of this investigation.

Sampling wheat for deoxynivalenol.

The variability associated with testing wheat for deoxynivalenol (DON) was measured using a 0.454 kg sample, a Romer mill, 25 g of comminuted subsample and the Romer Fluoroquant analytical method. The total variability was partitioned into sampling, sample preparation, and analytical variability components.